xcept for property which the Secretary specifically determines is needed for interpretive or resources management purposes of the seashore, the owner of improved property or of agricultural property on the date of its acquisition by the Secretary under sections 459c to 459c-7 of this title may, as a condition of such acquisition, retain for himself and his or her heirs and assigns a right of use and occupancy for a definite term of not more than twenty-five years, or, in lieu thereof, for a term ending at the death of the owner or the death of his or her spouse, whichever is later.